1. Field of the Invention
The invention relates to a turbomachine, in particular a gas turbine, with a rotor and a stator and with an axial sealing device arranged between the rotor and the stator.
2. Brief Description of the Related Art
So that as high efficiency as possible can be generated in modern turbomachines, particularly in gas turbines or compressors, it is desirable to seal off the turbomachine effectively and thereby avoid both a loss of hot gases driving the turbomachine and an eruption of cooling gases which lower the temperature within the turbomachine and consequently adversely influence efficiency. A particular problem in sealing off turbomachines of this type arises especially when the sealing device is arranged between structural components which move in relation to one another. This is the case, for example, in a sealing device which is arranged between a rotating rotor and a stator which is stationary in relation to the latter. Additional relative movements of the sealing device components lying opposite one another occur at the transition from the thermally cold state of rest into the hot operating state on account of thermal expansion and of mechanical load in the case of different material properties of the load-bearing parts.
Normally, in sealing devices of this type, a sealing contour stepped radially on the stator side is provided, which has regions projecting and retracting in the direction of the rotor. In this case, on the rotor side, a plurality of sealing fins projecting in the direction of the stator are arranged, which engage in each case into adjacent retracting regions of the stator-side sealing contour. The sealing fins and the associated sealing contours can thus provide what is known as a labyrinth seal, the sealing action of which may additionally be increased, in that the sealing contour is produced from a strippable material and the sealing fins are produced from a stripping material; when the turbomachine is in operation, the sealing fins come to bear against the sealing contours or even dig into them. Such digging, however, causes a wear of the sealing device which is not to be underestimated, with the result that the latter slowly loses its sealing action again over a period of time.
In addition to reducing the efficiency of the turbomachine, a poor sealing property of the sealing device also results in an eruption of hot gas in the sealing region, which speeds up an oxidation process and therefore also corrosion.